A suicide bomber from an al Qaeda-linked militant group hit the Syrian defence minister's hometown.

The opposition observatory said a Saudi militant who came to Syria to fight with the country's al Qaeda affiliate, al-Nusra Front, blew himself up today at an army checkpoint in the village of Rahjan in central Hama province.

Rahjan, in a remote eastern part of Hama, is the ancestral home of Defence Minister "Fahd al-Freij", who is now living in the capital Damascus.

"This is a message from al-Nusra fighters to Freij: 'You cannot protect your own relatives'", said Rami Abdelrahman, head of the opposition Observatory, a Britain-based group.

Abdelrahman said the attack by the suicide bomber, who blew himself up in an explosives-rigged car, sparked clashes around Rahjan between the Syrian army and militants that raged until dawn on Tuesday, adding that five al-Nusra fighters and were killed as were three combatants from other militant groups.